Salt grass (Distichlis spicata) is a hardy perennial grass that has mastered survival in environments where high salt concentrations make life impossible for most other plants. This widespread species, native to the Americas, is a true halophyte, meaning it thrives in saline conditions. Its common name comes from its remarkable ability to manage the excess salt it absorbs. This ability to flourish is due to specialized physiological mechanisms that allow it to colonize and dominate salty plains, coastal marshes, and desert basins across North America.
Identifying Salt Grass
Salt grass is typically a low-growing plant, rarely exceeding 35 inches in height, with rigid, erect stems. Its leaves are stiff, narrow, and often bluish-green, arranged in two distinct rows on opposite sides of the stem, giving it a characteristic two-ranked appearance. The plant forms dense, expansive mats primarily due to its vigorous, underground stems called rhizomes.
These rhizomes are scaly and sharp-tipped, allowing the plant to penetrate and spread through hard, compacted, or alkaline soils. The species is also dioecious, meaning individual plants are either exclusively male or exclusively female. The male and female flowers are borne on separate plants, appearing as yellowish or purplish spike-like clusters from late spring into the fall.
The Unique Adaptation to Saline Environments
Salt grass is classified as a recretohalophyte, meaning it survives high salinity by actively removing salt from its tissues. Unlike many other plants that exclude salt at the roots, this species readily absorbs sodium and chloride ions from the soil. The survival mechanism involves specialized structures known as salt glands, which are located on the surface of its leaves.
These salt glands excrete excess salt, preventing it from reaching toxic levels within the plant’s metabolic cells. Each gland is a minute structure composed of specialized cells that transport ions like sodium and chloride out of the leaf tissue and onto the leaf surface. This process causes the leaves to often appear dusted with white, crystalline flakes, which are the visible remnants of the excreted salt.
The salt is pushed out through a cap cell of the gland, where it crystallizes as the water evaporates. This active excretion maintains a stable internal salt concentration, allowing the plant to continue essential functions like photosynthesis despite the highly saline environment. The ability to “sweat” the salt makes this grass one of the few species capable of thriving in conditions that would cause severe osmotic stress and death in most other plants.
Geographic Range and Preferred Habitats
Distichlis spicata is widely distributed across the continent, thriving in a variety of coastal and inland saline environments. Along the coasts, it is a prominent species in salt marshes, estuaries, and back dune areas. In these settings, the plant endures regular inundation by brackish or saltwater.
Inland, the grass is equally adaptable, dominating environments such as salt flats, alkaline meadows, and desert basins where water evaporation leaves behind concentrated salt deposits. Notable inland locations include the areas surrounding the Great Salt Lake in Utah and various alkali flats in the Great Basin. Its extensive range, stretching from the Northwest Territories down to Mexico, demonstrates its remarkable tolerance for both coastal and arid, high-salinity soils.
Ecological Significance
Salt grass plays an important role in the stability and function of the harsh ecosystems it inhabits. Its dense, creeping network of rhizomes forms a thick sod that is highly effective at binding soil particles. This root system is instrumental in stabilizing shorelines and preventing erosion in dynamic environments like coastal marshes and river floodplains.
The grass also contributes to the local food web, providing both cover and forage for specific wildlife. The dense mats offer nesting cover for certain birds, and the plant is a food source for waterfowl and the Florida salt marsh vole. When the grass dies and decomposes, the resulting organic matter releases stored nutrients that become a food source for various marine invertebrates, including clams and crabs.